<?php

/**
 +----------------------------------------------------------
 * 字符串截取，支持中文和其他编码
 +----------------------------------------------------------
 * @static
 * @access public
 +----------------------------------------------------------
 * @param string $str 需要转换的字符串
 * @param string $start 开始位置
 * @param string $length 截取长度
 * @param string $charset 编码格式
 * @param string $suffix 截断显示字符
 +----------------------------------------------------------
 * @return string
 +----------------------------------------------------------
 */
function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
{
    if(function_exists("mb_substr"))
        return mb_substr($str, $start, $length, $charset);
    elseif(function_exists('iconv_substr')) {
        return iconv_substr($str,$start,$length,$charset);
    }
    $re['utf-8']   = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
    $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
    $re['gbk']    = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
    $re['big5']   = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
    preg_match_all($re[$charset], $str, $match);
    $slice = join("",array_slice($match[0], $start, $length));
    if($suffix) return $slice."…";
    return $slice;
}

/**
 * Smarty plugin
 * @package Smarty
 * @subpackage plugins
 *
 * Smarty plugin
 * Example:  {$time|time_format}
 */
function smarty_modifier_time_format($string) {
    $string = strtotime($string);
    $now = time();
    $return_str = '';
    $poss_time = ($now - $string) / 60;
    if ($poss_time < 60) {
        $return_str = ceil($poss_time) . "分钟前";
    } elseif ($poss_time <= 60 * 24) {
        $return_str = ceil($poss_time / 60) . "小时前";
    } elseif ($poss_time <= 7 * 60 * 24) {
        $return_str = ceil($poss_time / (60 * 24)) . "天前";
    } else {
        $return_str = "更早";
    }
    return $return_str;
}

?>
